package org.ccf.certified.util;

import com.auth0.jwt.JWT;
import com.auth0.jwt.JWTVerifier;
import com.auth0.jwt.algorithms.Algorithm;
import com.auth0.jwt.exceptions.JWTDecodeException;
import com.auth0.jwt.exceptions.TokenExpiredException;
import com.auth0.jwt.interfaces.DecodedJWT;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import java.util.Date;

/**
 * @author LiuFang
 * @date 2022/1/12
 */
public class JWTUtil {

    public static Logger log = LoggerFactory.getLogger(JWTUtil.class);

    // 过期时间5分钟
    private static final long EXPIRE_TIME = 1*60*1000;

    /**
     * 校验token是否正确
     * @param token 密钥
     * @param secret 用户的密码
     * @return 是否正确
     */
    public static boolean verify(String token, String username, String secret) throws TokenExpiredException{
        try {
            Algorithm algorithm = Algorithm.HMAC256(secret);
            JWTVerifier verifier = JWT.require(algorithm)
                    .withClaim("username", username)
                    .build();
            DecodedJWT jwt = verifier.verify(token);
            log.debug("认证通过：");
            log.debug("issuer: " + jwt.getIssuer());
            log.debug("username: " + jwt.getClaim("username").asString());
            log.debug("过期时间：      " + jwt.getExpiresAt());
            return true;
        } catch (Exception exception) {
            return false;
//            throw new TokenExpiredException("Token Timeout ... ");
        }
    }

    /**
     * 获得token中的信息无需secret解密也能获得
     * @return token中包含的用户名
     */
    public static String getUsername(String token) {
        try {
            DecodedJWT jwt = JWT.decode(token);
            return jwt.getClaim("username").asString();
        } catch (JWTDecodeException e) {
            return null;
        }
    }

    /**
     * 生成签名,5min后过期
     * @param username 用户名
     * @param secret 用户的密码
     * @return 加密的token
     */
    public static String signExpired(String username, String secret) {
        Date date = new Date(System.currentTimeMillis()+EXPIRE_TIME);
        Algorithm algorithm = Algorithm.HMAC256(secret);
        // 附带username信息
        return JWT.create()
                .withClaim("username", username)
                .withExpiresAt(date)
                .sign(algorithm);
    }

    /**
     * 生成签名,无时效限制
     * @param username 用户名
     * @param secret 用户的密码
     * @return 加密的token
     */
    public static String sign(String username, String secret) {
        Algorithm algorithm = Algorithm.HMAC256(secret);
        // 附带username信息
        return JWT.create()
                .withClaim("username", username)
                .withClaim("time",new Date().getTime())
                .sign(algorithm);
    }

}
